CN102854501B - Method for detecting distance and speed based on orthogonal baseband signals with any step length - Google Patents

Abstract

The invention discloses a method for detecting a distance and a speed based on orthogonal baseband signals with any step length, which is used for solving a technical problem of low detection speed as the existing radar needs to wait for receiving an echo of a signal sent for the first time and then sends the signal for the second time. The method adopts the following technical scheme: continuously sending a string of the orthogonal baseband signals with any step length; effectively authenticating through the echoes; carrying out signal decoding on echo integral of the one string of the orthogonal baseband signals with any step length; and separating the echoes of the baseband signals sent in different time. Therefore, the detection efficiency of the radar is improved.

Description

Based on distance, the speed detection method of any step-length digital orthogonal baseband signal

Technical field

The invention belongs to radar tracking performances areas, particularly relate to a kind of distance based on any step-length digital orthogonal baseband signal, speed detection method.

Background technology

Radar is the electronic equipment utilizing microwave region electromagnetic wave detection target, it is the detection means of obtaining information in modern war operational chain of command, the sensor collecting various military information, it have find that target range is far away, measure coordinates of targets and other parametric speed are fast, can the feature such as all weather operations; When radar system is contained in all kinds of optimal in structures such as aircraft, naval vessel, battlebus, guided missile, becoming precision strike implemented by weaponry guarantee to target, is the multiplier playing its operational performance; Radar is militarily widely used in the aspects such as warning, guiding, weapon control, scouting, measurement, navigation guarantee, enemy and we's identification and meteorological observation, is a kind of important military electronic technique equipment; The classification of radar has various ways, and dividing according to place platform has ground radar, airborne radar etc.; Divide according to operation wavelength and have metre wave radar, microwave radar etc.; Divide according to purposes and have air surveillance radar, instrumentation radar, early warning radar, weather radar, fire control or fire control radar, artillery radar, guidance radar etc.; Divide according to the target component measured and have D radar, three-dimensional radar etc.; Divide according to signal form and have pulsed radar, continuous wave radar etc.; The concrete purposes of various radar and structure are not quite similar, but citation form is consistent, comprise five elements: transmitter, emitting antenna, receiver, receiving antenna and display; Also have power-supply device, data record apparatus, anti-interference equipment, utility appliance etc.; Radar role is similar with eyes, its principle be the transmitter of radar equipment by bundle of lines electromagnetic wave energy directive space, sky a direction, be in the object that this side up and encounter electromagnetic wave back reflection; Radar antenna receives this reflection wave, delivers to receiving equipment and processes, and extracts some information of this object relevant, if target object is to the distance of radar, range rate or radial velocity, orientation, height etc.; Measuring distance is actual is measure the mistiming transmitted and between echoed signal, because electromagnetic wave is with light velocity propagation, just can be converted into the accurate distance of target accordingly; Measurement target orientation utilizes the sharp-pointed azimuth beam of antenna to measure, and measures the elevation angle and measure by narrow elevation beam, just can calculate object height according to the elevation angle and distance; Measuring speed is that radar is according to the frequency Doppler effect principle having relative motion to produce between self and target; The target echo frequency that radar receives is different from radar transmitter frequency, and both differences are called Doppler frequency; From Doppler frequency, one of extractible main information is the range rate between radar and target; When in the same space resolution element that target and interference noise are present in radar simultaneously, radar utilize Doppler frequency between them difference can from interference noise detection and tracking target; Day and night is the advantage of radar all can detect remote target, and not by the stop of mist, Yun Heyu, has feature that is round-the-clock, round-the-clock, and have certain penetration capacity; Therefore, it not only becomes military requisite electronics, and is widely used in socio-economic development if weather forecast, resource detection, environmental monitoring and scientific research are as celestial body research, atmospheric physics, ionospheric structure research etc.; Spaceborne and airborne synthetic aperture radar has become sensor very important in current remote sensing fields, and take ground as the accurate shape that the radar of target can detect ground, its spatial resolution can reach several meters to tens meters, and irrelevant with distance; Radar shows good application potential in freshwater monitoring, sea ice monitoring, soil moisture investigation, forest assessment, geologic examination etc.But, sending next measurement usually need wait-receiving mode to the echoed signal transmitted when pre-test when radargrammetry distance after again and transmit, to transmit and mistiming between echoed signal calculates distance by measuring; This scheme speed of detection is low, the performance of serious restriction radar performance.

Summary of the invention

In order to overcome the deficiency that existing radar second time transmission signal demand wait-receiving mode causes speed of detection low to sending signal echo for the first time, the invention provides a kind of distance based on any step-length digital orthogonal baseband signal, speed detection method.The method adopts and sends a string any step-length digital orthogonal baseband signal continuously, by carrying out the decoding between signal to the echo integration of a string any step-length digital orthogonal baseband signal again after the effective certification of echo, by the baseband signal echo free process that different time sends, the detection efficiency of radar can be improved.

The technical solution adopted for the present invention to solve the technical problems is: a kind of distance based on any step-length digital orthogonal baseband signal, speed detection method, be characterized in comprising the following steps:

Step one, transmission signal are:

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\ξ}}_i\left\{\mathrm{i\ω}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\Σ}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\Σ}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-$

$u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i+1}{\mathrm{\Σ}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]\}$

In formula,

$\left.\begin{array}{c}{\mathrm{\ξ}}_1\left(\mathrm{\ωt}\right)=\cos \left[a{\cos }^{-1}(1-2\mathrm{\ωt}/b)\right]\\ {\mathrm{\ξ}}_2\left(\mathrm{\ωt}\right)=2{\mathrm{\ξ}}_1\left(\mathrm{\ωt}\right)\·{\mathrm{\ξ}}_1\left(\mathrm{\ωt}\right)-1\\ \·\\ \·\\ \·\\ {\mathrm{\ξ}}_{i+1}\left(\mathrm{\ωt}\right)=2{\mathrm{\ξ}}_1\left(\mathrm{\ωt}\right){\mathrm{\ξ}}_i\left(\mathrm{\ωt}\right)-{\mathrm{\ξ}}_{i-1}\left(\mathrm{\ωt}\right)\end{array}\right\}$ I=2,3 ..., n-1,0≤t≤NT, b=NT is the recursive form of any step-length orthogonal polynomial, and a is any real number, and ω is angular frequency, and 0≤t≤NT is the time, and n, N are integer,

$u\left(t\right)=\left\{\begin{array}{cc}0& t<0\\ 1& t\&GreaterEqual;0\end{array}\right.,$

T _inijfor ξ _jthe origin identification symbol duration of (j ω t), T _endjfor ξ _jthe ending identifier duration of (j ω t), T _jfor ξ _jthe durations of (j ω t) signal;

Coded system is: ξ ₁the origin identification symbol of (ω t), ξ ₁(ω t), ξ ₁(ω t) ending identifier ... ξ _ithe origin identification symbol of (i ω t), ξ _i(i ω t), ξ _i(i ω t) ending identifier ..., ξ _nthe origin identification symbol of (n ω t), ξ _n(n ω t), ξ _nthe ending identifier of (n ω t);

Step 2, by echoed signal certification ξ _ithe origin identification of (i ω t) accords with and ends up identifier and echo time;

Step 3, according to function

${\&Integral;}_{t_0}^{t_1}{\mathrm{\&phi;}}^2\left(t\right)\mathrm{dt}={\&Integral;}_{t_0}^{t_1}{\mathrm{\&psi;}}^2\left(t\right)\mathrm{dt}$

The speed of target travel, echo time are estimated;

In formula, the echo function that φ (t) is radar detection,

$\mathrm{\&psi;}\left(t\right)=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&xi;}}_i\left\{i(1+\mathrm{signr}\frac{{2v}_{\mathrm{ri}}}{c})\mathrm{\&omega;}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\&CenterDot;$

$\left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i+1}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}$

Δ T _jfor receiving ξ _jthe time delay of (j ω t) signal, c is the light velocity, and the angle between definition radar line of sight and object velocity vector is θ, v _ri=v _icos θ, v _ibe the amplitude of the relative radar speed vector of target of the i-th subwave detection, when gtoal setting radar motion, the spacing of radar and target reduces, and its echo frequency equals transmission frequency and adds Doppler shift and signr=1, and echo frequency is greater than emission signal frequency; Otherwise when target is away from radar motion, the spacing of radar and target increases, and its echo frequency equals transmission frequency and deducts Doppler shift, and namely signr=-1 echo frequency is less than emission signal frequency; When target transfixion, there is not Doppler effect, i.e. signr=0.

The invention has the beneficial effects as follows: send a string any step-length digital orthogonal baseband signal continuously owing to adopting, by carrying out the decoding between signal to the echo integration of a string any step-length digital orthogonal baseband signal again after the effective certification of echo, by the baseband signal echo free process that different time sends, improve the detection efficiency of radar.

Below in conjunction with embodiment, the present invention is elaborated.

Embodiment

The distance, the speed detection method concrete steps that the present invention is based on any step-length digital orthogonal baseband signal are as follows:

1, sending signal is:

$\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&xi;}}_i\left\{\mathrm{i\&omega;}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-$

$u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i+1}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]\}$

Wherein:

$\left.\begin{array}{c}{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)=\cos \left[a{\cos }^{-1}(1-2\mathrm{\&omega;t}/b)\right]\\ {\mathrm{\&xi;}}_2\left(\mathrm{\&omega;t}\right)=2{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)\&CenterDot;{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)-1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ {\mathrm{\&xi;}}_{i+1}\left(\mathrm{\&omega;t}\right)=2{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right){\mathrm{\&xi;}}_i\left(\mathrm{\&omega;t}\right)-{\mathrm{\&xi;}}_{i-1}\left(\mathrm{\&omega;t}\right)\end{array}\right\}$ i=2，3，…，n-1，0≤t≤NT，b=NT

For Chebyshev(Chebyshev) recursive form of orthogonal polynomial, a is any real number, and T is the sampling period, and ω is angular frequency, and t >=0 is the time,

$u\left(t\right)=\left\{\begin{array}{cc}0& t<0\\ 1& t\&GreaterEqual;0\end{array}\right.,$

T _inijfor ξ _jthe origin identification symbol duration of (j ω t), T _endjfor ξ _jthe ending identifier duration of (j ω t), T _jfor ξ _jthe durations of (j ω t) signal, symbol definition is identical in full;

Coded system is: ξ ₁the origin identification symbol of (ω t), ξ ₁(ω t), ξ ₁(ω t) ending identifier ... ξ _ithe origin identification symbol of (i ω t), ξ _i(i ω t), ξ _i(i ω t) ending identifier ..., ξ _nthe origin identification symbol of (n ω t), ξ _n(n ω t), ξ _nthe ending identifier of (n ω t);

2, by echoed signal certification ξ _ithe origin identification of (i ω t) accords with and ends up identifier and echo time;

3, according to function

$\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}{\mathrm{\&phi;}}^2\left(t\right)\mathrm{\&Delta;t}=\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&psi;}}^2\left(t\right)\mathrm{\&Delta;t}$

Can estimate the speed of target travel, echo time;

Wherein, the echo function that φ (t) is radar detection, Δ t=(t ₁-t ₀)/M, M is integer;

$\mathrm{\&psi;}\left(t\right)=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&xi;}}_i\left\{i(1+\mathrm{signr}\frac{{2v}_{\mathrm{ri}}}{c})\mathrm{\&omega;}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\&CenterDot;$

$\left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i+1}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}$

Δ T _jfor receiving ξ _jthe time delay of (j ω t) signal, c is the light velocity, and the angle between definition radar line of sight and object velocity vector is θ, v _ri=v _icos θ, v _ibe the amplitude of the relative radar speed vector of target of the i-th subwave detection, when gtoal setting radar motion, the spacing of radar and target reduces, and its echo frequency equals transmission frequency and adds Doppler shift and signr=1, and echo frequency is greater than emission signal frequency; Otherwise when target is away from radar motion, the spacing of radar and target increases, and its echo frequency equals transmission frequency and deducts Doppler shift, and namely signr=-1 echo frequency is less than emission signal frequency; When target transfixion, there is not Doppler effect, i.e. signr=0.

Claims (1)

1., based on distance, the speed detection method of any step-length digital orthogonal baseband signal, it is characterized in that comprising the following steps:

Step one, transmission signal are:

$\begin{array}{c}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&xi;}}_i\left\{\mathrm{i\&omega;}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-\\ u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-\underset{j=-n}{\overset{i+1}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]\}\end{array}$

In formula,

$\left.\begin{array}{c}{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)=\cos \left[a{\cos }^{-1}(1-2\mathrm{\&omega;t}/b)\right]\\ {\mathrm{\&xi;}}_2\left(\mathrm{\&omega;t}\right)=2{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)\&CenterDot;{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right)-1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ {\mathrm{\&xi;}}_{i+1}\left(\mathrm{\&omega;t}\right)=2{\mathrm{\&xi;}}_1\left(\mathrm{\&omega;t}\right){\mathrm{\&xi;}}_i\left(\mathrm{\&omega;t}\right)-{\mathrm{\&xi;}}_{i-1}\left(\mathrm{\&omega;t}\right)\end{array}\right\}$ i＝2，3，…，n-1，0≤t≤NT，b＝ωNT

For the recursive form of any step-length orthogonal polynomial, a is any real number, and ω is angular frequency, and 0≤t≤NT is the time, and n, N are integer,

$u\left(t\right)=\left\{\begin{array}{cc}0& t<0\\ 1& t\&GreaterEqual;0\end{array}\right.,$

T _inijfor ξ _jthe origin identification symbol duration of (j ω t), T _endjfor ξ _jthe ending identifier duration of (j ω t), T _jfor ξ _jthe durations of (j ω t) signal;

Coded system is: ξ ₁the origin identification symbol of (ω t), ξ ₁(ω t), ξ ₁(ω t) ending identifier ... ξ _ithe origin identification symbol of (i ω t), ξ _i(i ω t), ξ _i(i ω t) ending identifier ... ξ _nthe origin identification symbol of (n ω t), ξ _n(n ω t), ξ _nthe ending identifier of (n ω t);

Step 2, by echoed signal certification ξ _ithe origin identification of (i ω t) accords with and ends up identifier and echo time;

Step 3, according to function

${\&Integral;}_{t_0}^{t_1}{\mathrm{\&phi;}}^2\left(t\right)\mathrm{dt}={\&Integral;}_{t_0}^{t_1}{\mathrm{\&psi;}}^2\left(t\right)\mathrm{dt}$

The speed of target travel, echo time are estimated;

In formula, the echo function that φ (t) is radar detection,

$\begin{array}{c}\mathrm{\&psi;}\left(t\right)=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&xi;}}_i\left\{i(1+\mathrm{signr}\frac{{2v}_{\mathrm{ri}}}{c})\mathrm{\&omega;}\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\&CenterDot;\\ \left\{u\right[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})]-u[t+(T_{\mathrm{ini}(-n)}+T_{-n})-{\mathrm{\&Delta;T}}_j-\underset{j=-n}{\overset{i+1}{\mathrm{\&Sigma;}}}(T_{\mathrm{inij}}+T_j+T_{\mathrm{endj}})\left]\right\}\end{array}$

Δ T _jfor receiving ξ _jthe time delay of (j ω t) signal, c is the light velocity, and the angle between definition radar line of sight and object velocity vector is θ, v _ri=v _icos θ, v _ibe the amplitude of the relative radar speed vector of target of the i-th subwave detection, when gtoal setting radar motion, the spacing of radar and target reduces, and its echo frequency equals transmission frequency and adds Doppler shift and signr=1, and echo frequency is greater than emission signal frequency; Otherwise when target is away from radar motion, the spacing of radar and target increases, and its echo frequency equals transmission frequency and deducts Doppler shift, i.e. signr=-1, and echo frequency is less than emission signal frequency; When target transfixion, there is not Doppler effect, i.e. signr=0.